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Volume 50, Issue 2
Displaying 1-14 of 14 articles from this issue
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Tetsuya Tanigami, Lin-hai Zhu, Kazuo Yamaura, Shuji Matsuzawa1994 Volume 50 Issue 2 Pages 53-61
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSPoly (vinyl alcohol) samples with different degrees of saponification (DS) snd polymerization (_??_), and different amounts of residual sodium acetate were melt-spun and drawn under the conditions which suppressed seriously coloring of filaments. The tensile modulus (E) and strength (σb) of drawn filaments increased almost linearly with the birefringence. The highest E and σb values achieved by this process were 12-18GPa and 0.9-1.1GPa, respectively. The crystallinity and drawability of as-spun filaments decreased by the thermal degradation during spinning, especially in high _??_ samples (_??_ > 1000). When high _??_ was used, however, the _??_ could be reduced to the optimum value (_??_ < 1000) during processing with the help of residual sodium acetate. The samples with lower DS (<90mol%) showed lower E and σb values due to the resultant lower crystallinity.View full abstractDownload PDF (1741K) -
Kuo Hsiung Huang, Motomu Arisawa, Masaru Yoneyama, Kozo Arai1994 Volume 50 Issue 2 Pages 62-67
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThermal and mechanical properties of poly-(4-methyl-m-phenyleneterephthalamide) (PMMTA) fibers were investigated. PMMTA fibers showed excellent thermal properties comparable to Nomex fibers, but exhibited lower initial modulus and breaking stress than those of Nomex fibers. Intermoleculer cross-links were formed in PMMTA fibers when they were heat-treated at temperatures above 280°C. The striking decreases in breaking stress and strain of the fibers treated at 260°C were considered to be due to the stress concentration near the cross-linking points. Mechanical properties of PMMTA fibers were greatly improved by the treatment with water at 140°C. Dynamic viscoelasticity measurements showed four dispersion peaks located around - 32, 5, 225, and 365°C, which were attributed to the γ, β, β∗ and α relaxation, respectively. By heat-treatment at 300°C, the α dispersion peak shifted to higher temperature at ca. 400°C and the γ dispersion peak shifted to lower temperature at ca. -50°C These were likely to be related to the formation of cross-links followed by the disordering of molecular chains in the amorphous region.View full abstractDownload PDF (463K) -
Kuo Hsiung Huang, Masaru Yoneyama, Kozo Arai, Kazuhiko Koiwai1994 Volume 50 Issue 2 Pages 68-72
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThermal and dynamic viscoelasticity of poly (4-methyl-m-phenyleneterephthalamide) (PMMTA) films were investigated and compared with those of Nomex films. In DTA curves, PMMTA and Nomex films showed glass transition around 293°C and 273°C, respectively. By heat-treatment at 280 to 300°C, intermolecular crosslinks were formed in PMMTA films but not in Nomex films. From dynamic viscoelasticity measurements, three dispersion peaks for PMMTA were observed at ca. -45, 210 and 350°C, which were attributed to γ, β∗ and α relaxation, respectively. For heat-treated PMMTA film at 300°C, the α dispersion peak shifted to higher temperature at ca. 378°C, and the apparent activation energy for α dispersion, 174 kcal/mol, was considerably greater than that obtained for the untreated film, 110 kcal/mol. On the contrary, for heat-treated Nomex films no perceptible change was observed for the α relaxation. It was suggested, therefore, that in PMMTA the molecular motion of chains was restricted by the cross-links formed. By the heat-treatment at 300°C, the γ dispersion peak of PMMTA film shifted to lower temperature at ca. -60°C. This was considered to be due to the breakdown of hydrogen bonds caused by the formation of cross-links.View full abstractDownload PDF (381K) -
Tooru Taga1994 Volume 50 Issue 2 Pages 73-80
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSIn the graft copolymerization of styrene onto cellulose using benzoyl peroxide (BPO) as initiator graft copolymer was not formed and at the same time the phenomenon suggesting the consumption of BPO with cellulose was observed. Model reactions revealed that the degradation of BPO was accelerated with cellulose and that cellulose was readily oxidized with BPO. These results may imply that BPO/cellulose redox system lacks the ability to intiate graft copolymerization. On the other hand, α, α'-azobisisobutyronitrile was confirmed to bring about the graft copolymerization induced by the transfer reaction of propagating radicals. In this case, the initiator was not consumed with cellulose.View full abstractDownload PDF (543K) -
Nobuhiko Nakano, Sumiko Hasegawa, Yukimichi Nakao1994 Volume 50 Issue 2 Pages 81-86
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSPolymer-metal cluster composites, in which ultrafine particles of colloidal metals were well dispersed in polymer matrix, were prepared by dissolving the metal compounds in monomer, polymerization, solidification, and deoxidation by heating. From the measurement of the thermomechanical properties of polymer-metal cluster composites, the optimum condition for the heat treatment and the mechanism of elastic modulus reinforcement were discussed. The elastic modulus of the composite increased as much as two times than that of the matrix polymer by adding only 0.005 volume percent of palladium ultrafine particles with a diameter of 10-20 _??_. This peculiarity in elastic modulus increase was considered to be caused by the good unification of the ultrafine particles and the matrix. It was shown that the mechanism for the modulus increase can possibly be described based on the rule of mixture of composites taking into account the existence of interfacial binding regions. In such composite materials, it was suggested that the mechanical properties can show remarkable increase with a decrease in the diameter of particles.View full abstractDownload PDF (915K) -
Harumi Ikuno, Motoko Komaki, Toshinari Nakajima1994 Volume 50 Issue 2 Pages 87-91
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe influence of humidity on the fading rate of C. I. Fluorescent Brightener 351 was investigated.
Fading rate under dry conditions decreased with increasing dye concentration, whereas at the moisture level of 7.7 g•m-3 it was independent of the dye concentration. At the moisture level of 14.9 g•m-3, on the other hand, the fading rate increased with increasing dye concentration. Water in cellophane accelerated the fading, but the addition of sodium chloride on dyeing depressed the fading. A kinetic analysis suggested the participation of bimolecular fading mechanism.View full abstractDownload PDF (376K) -
Limin Bao, Masayuki Takatera, Akira Shinohara1994 Volume 50 Issue 2 Pages 92-96
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
JOURNAL FREE ACCESSThe dynamic bending response of a woven fabric was theoretically estimated from its static bending property including hysteresis. The hysteresis loop obtained by pure bending test was simulated by the Rate madel, based on which the equivalent flexural rigidity and damping coefficient were estimated. The response of the model strip of fabric with these parameters to forced oscillation was analyzed by a nonlinear FEM. The results showed that the calculated results agreed well with the experimental ones in value as well as in dependence on the amplitude of forced vibration.View full abstractDownload PDF (345K) -
Prospect and StrategyYUKIO DOI1994 Volume 50 Issue 2 Pages P43-P47
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
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DAVID R. BUCHANAN1994 Volume 50 Issue 2 Pages P48-P54
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
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MARIO BONA1994 Volume 50 Issue 2 Pages P55-P59
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
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TOSHIICHI SOEN1994 Volume 50 Issue 2 Pages P60-P63
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
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TERUHIKO MATSUO1994 Volume 50 Issue 2 Pages P64-P68
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
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SHUICHI EMORI1994 Volume 50 Issue 2 Pages P69-P74
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
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OSAMU TANIDA1994 Volume 50 Issue 2 Pages P75-P79
Published: February 10, 1994
Released on J-STAGE: November 28, 2008
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